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pumping electron positron pairs from a well potential

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www.nature.com/scientificreports OPEN Pumping Electron-Positron Pairs from a Well Potential Qiang Wang1, Jie Liu1,2,3 & Li-bin Fu1,2,3 received: 16 December 2015 accepted: 14 April 2016 Published: 29 April 2016 In the presence of very deep well potential, electrons will spontaneously occupy the empty embedded bound states and electron-positron pairs are created by means of a non-perturbative tunneling process In this work, by slowly oscillating the width or depth, the population transfer channels are opened and closed periodically We find and clearly show that by the non-synchronous ejections of particles, the saturation of pair number in a static super-critical well can be broken, and electrons and positrons can be pumped inexhaustibly from vacuum with a constant production rate In the adiabatic limit, final pair number after a single cycle has quantized values as a function of the upper boundary of the oscillating, and the critical upper boundaries indicate the diving points of the bound states In a static, uniform and very strong electric field, the QED vacuum may break down and decay into electron-positron pairs due to a quantum tunneling effect1–3 Time dependent fields can also generate pairs through another mechanism, that electrons in Dirac Sea transit into positive states via photon absorption 4–6 Positron beam is a nondestructive probe in positron annihilation spectroscopy for the study of atomic-scale structure of materials7,8 Pair creation is an important issue in the study of laser-vacuum, laser-matter interaction, and also in astrophysics since it is thought to be associated with the supernova explosion9 In laboratory, pairs have been generated by the collision of heavy ions10 and the collision of an intense laser pulse and a 46 GeV electron beam11 Recently, MeV positron beam with high density was obtained through laser-accelerated electrons irradiating high-Z solid targets12 However, due to the presently unfeasible Schwinger critical field strength, which is about 1016 V/cm and correspond to a laser intensity of about 1029 W/cm2, pairs created from pure laser light has not been observed yet In light of the rapid advance of laser technology a good theoretical understanding of the pair creation in strong laser fields becomes highly desirable13 For a well potential of depth V0, if V0 >  2c2, the domain c2− V0 

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